1. Field of the Invention
The present invention is directed to producing low DE starch hydrolysates, which involves fractionating a starch hydrolysate having a DE greater than about 18 using a nanofiltration membrane under nanofiltration conditions effective to result in low DE starch hydrolysate having a DE of less than about 25; resultant low DE starch hydrolysate products; blends of such low DE starch hydrolysates with other substances; and emulsions and encapsulates prepared using such low DE starch hydrolysates.
2. Description of the Related Art
Maltodextrins, a low DE starch hydrolysate with a dextrose equivalent (DE) of not more than about 20, e.g., 4 to 20, have bland taste, low sweetness, and low hygroscopicity. Such products are useful as bases for the preparation of food items as well as for bodying agents and as additives having non-sweet, water-holding, non-hygroscopic characteristics. Other applications include their use as a carrier for synthetic sweeteners, as spray drying adjunct, as bulking, bodying or dispersing agents, as moisture holding agents, and as energy source in sports drinks.
Most commercially available maltodextrins in the world market produced by known technology are in the solid form or crystalline form due to retrogradation or haze formation or microbial instability in liquid form. However, there is a demand for a maltodextrin in its liquid form which exhibits extreme clarity, low viscosity, and will not develop retrogradation upon storage at room temperature.
There have been low DE liquid maltodextrins produced using conventional processes, such as enzyme conversion, chromatographic fractionation and membrane fractionation. However, the products produced suffered disadvantages including instability in liquid form or high viscosity.
U.S. Pat. No. 3,974,032 is directed to a haze resistant low DE liquid starch hydrolysate which has its weight average molecular weight to its number average molecular weight ratio less than about 20, and has less than about 20% by weight, dry basis, of starch oligosaccharides having a degree of polymerization greater than about 200 (DP200+). The low DE starch hydrolysate was prepared by enzymatically hydrolyzing starch dextrins having a degree of branching of at least about 7.
U.S. Pat. Nos. 3,974,033 and 3,974,034 disclose methods to produce a low DE maltodextrin and improve stability by enzymatic hydrolysis of oxidized starch. The maltodextrin is characterized as being haze-free for long period of time at high solids concentration. The maltodextrin is prepared by first liquefying a highly oxidized starch with acid or enzyme to a DE not substantially above about 7; and, in a subsequent step, converting the oxidized and liquefied starch with a bacterial alpha-amylase enzyme preparation to achieve a maltodextrin product having a DE not substantially above about 20.
U.S. Pat. No. 4,298,400 discloses another enzyme hydrolysis method to produce non-haze low DE liquid starch hydrolysates. The product, prepared by two step hydrolysis both using bacterial alpha amylase, has a descriptive ratio higher than 2.0, and, therefore, exhibits non-haze property.
U.S. Pat. No. Re. 30,880 discloses a similar product and a similar process except that the first step hydrolysis was accomplished by acid instead of enzyme hydrolysate.
U.S. Pat. No. 4,840,807 discloses a fractionation method to produce liquid low DE branched maltodextrins. The process comprises the steps of reacting alpha-amylase with starch to produce a starch hydrolysate in the DE range of 10 to 35, and then contacting the resulting saccharified solution with a gel-type filter agent, thereby selectively fractionating the branched dextrin and linear oligo-saccharides. The gel-type filtering agent is an ion exchange resin and the fractionation system is a simulated moving bed. The resulted branched oligosaccharides has a mean molecular weight of from about 800 and to about 16,000 with a corresponding DE from about 20 to about 1.
Membrane separation is known to fractionate polysaccharides of sugars. Waniska et al. (Journal of Food Science, Vol. 45 (1980), 1259) discloses the fractionating ability of three ultra filtration (UF) membranes compared with gel permeation and chromatography for separating oligosaccharides (DP5-20) from lower molecular sugar. Birch et al. (Die Starke 26. Jahrg. 1974/Nr. 7, 220) discloses the fractionation of glucose syrups by reverse osmosis (RO) which offers a means for the manufacture of several new types of syrup, and which enables entire groups of sugars to be eliminated under selected conditions. Products in the range 43-80 DE or 15-43 DE can be obtained using suitable combinations of different membranes. Kearsley et al. (Die Starke 28. Jahrg. 1976/Nr. 4, 138) discloses the reverse osmosis(RO) of glucose syrups and ultra filtration (UF) operations to isolate specific groups of sugars, high or low molecular weight or both, from the syrup. Sloan et al. (Preparative Biochemistry, 15(4), 1985, 259-279) discloses the molecular filtration of ultra filtration (UF) membranes to concentrate oligosaccharides with degrees of polymerization above 10 from corn starch hydrolysate. It is not believed that any of these processes has been used to make a non-retrograded maltodextrin having low viscosity.
U.S. Pat. No. 3,756,853 (1973) discloses a reverse osmosis (RO) membrane process for making non-hazing low DE starch hydrolysate. The product was produced by concentrating a feed corn syrup of 20 to 40 DE through a cellulose acetate reverse osmosis (RO) membrane until the DE of the retentate has been reduced to between about 5 to about 18.
Those concerned with low DE starch hydrolysates recognize the need for an improved low DE starch hydrolysate, particularly in liquid form, and more particularly, in blends thereof with other substances.
Substantial research has been directed to the problem of inherent instability of emulsions or multiphase systems, defined as thermodynamically metastable or unstable systems. Emulsion stability is a complicated phenomenon and a function of many variables, for example, viscosity, temperature, size distribution of internal phase droplets, stirring speed and time, surfactant type and concentration, phase ratio and composition, conductivity, and dielectric constant (P. Sherman "Emulsion Science", Academic press, N.Y, 2nd. Ed. (1988); I. Abou-Nemeh and A. P. Van-Peteghem "Some Aspects of Emulsion Instability Using Sorbitan Monooleate (Span 80) as a Surfactant in Liquid Emulsion Membranes" Chem.-Ing, Tech. 62(5), 420-3, (1990); I. Abou-Nemeh and A. P. Van-Peteghem "Membrane Aging and Related Phenomena in liquid Surfactant Membranes Process", Sep.Sci.Technol. 29 (6), 727-41, (1994)).
For example, in the case of O/W emulsions, of particular use in encapsulation, there is a continuous breakdown of emulsion, where the internal phase droplets (i.e. oil) collide with each other to form bigger ones. If this process continues unabatedly, it will result in coalescence of the dispersed phase droplets, and consequently, this will lead to phase separation.
Accordingly, those concerned with the art of emulsions recognize the need for improved emulsion compositions exhibiting long-term stability of emulsions comprising, for example, flavors, oils, fragrances, dyes, insecticides, biologically active drugs, etc.
Further it is well known and scientifically documented in the art of encapsulation of volatiles, oils, fragrances, etc., that for the latter to be fixed and encapsulated in a glassy-type substrate, it is recommended to have a certain composition which contains a specific material, i.e. high molecular weight oligosaccharides, maltodextrins, starch, etc., which will enhance the film forming properties of the mixture and boost its encapsulative ability for spray-drying or extrusion purposes (U.S. Pat. Nos. 4,689,235; 5,124,162; 5,087,461; 5,786,017; 5,506,353; 5,780,090; 5,695,802; 3,764,346). However, encapsulation with conventional starch hydrolysates suffers from a variety of problems, including: high viscosity of the low DE starch hydrolysate substrate, low loading capacity, poor stability of the encapsulate, and formation of colored byproducts.
Accordingly, those concerned with the art of encapsulation recognize the need for improved encapsulation compositions that are stable, exhibit improved loading capacity and retention of, for example, flavors, oils, fragrances, dyes, insecticides, drugs, fine and benign chemicals, etc., and which may be antioxidant-free and be manufactured using substrates at relatively low dry solids content with superior film forming capability and encapsulative ability.